explain xkcd - User contributions [en]

2319: Large Number Formats

2020-06-14T06:46:06Z

Ajlee2006: color looks more like

{{comic
| number = 2319
| date = June 12, 2020
| title = Large Number Formats
| image = large number formats-2.png
| titletext = 10^13.4024: A person who has come back to numbers after a journey deep into some random theoretical field
}}

==Explanation==
{{incomplete|Created by ABRAHAM LINCOLN. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic shows what the way you write large numbers says about you. Different people use different methods to express large numbers. And this comic claims it can tell something about you based on the way you format large numbers. In this way the comic is similar in idea as [[977: Map Projections]], where it was your choice of map projections that could tell something about you.

See the [[#Table of types|table]] below for each of the 10 different ways to express large numbers, plus the 11th mentioned in the title text.

The number used as an example is the [https://www.wolframalpha.com/input/?i=Distance+to+Jupiter+in+inches approximate distance] from the planet {{w|Earth}} to the planet {{w|Jupiter}} as of the release day of the comic on June 12th 2020, in {{w|inch|inches}} (1 inch = 2.54 cm).

Two days after the release of the comic the following text could be found on [https://theskylive.com/jupiter-info Jupiter info] on [https://theskylive.com/ The Sky Live].
:The distance of Jupiter from Earth is currently 640,084,108 kilometers, equivalent to 4.278698 Astronomical Units. Light takes 35 minutes and 35.0908 seconds to travel from Jupiter and arrive to us.

64,008,410,800,000 cm / 2.54 inches/cm = 25,200,161,732,283 inches - much less than the number used in the comic. But Jupiter's distance to Earth changes quite fast, and was decreasing at the time of the comics release.

According to a graph of the distance as a function of time on The Sky Live, the distance on the release day was 643,1 million km. This will give 25,313 which the used number will round to. But still it is quite far from the one used.

The used number 25,259,974,097,204 is equivalent to 641,6 million km. On June 13th the distance is given as 641,7 million km in the graph on The Sky Live, very close to the number used. As this was the day after the release of this comic, it seems like [[Randall]] used a different distance than the exact one for the release day. Could also be that he used an average for June which would be 642 million km based on the average of the distance on June and July 1st.

==Table of types==
{| class="wikitable"
|-
! Number
! Type of person
! Notes
|-
| 25,259,974,097,204
| Normal Person
| This is the full number, 25259974097204, written out in the normal fashion, with commas to indicate powers of 1000. Although writing out the number in full is indeed a common action for normal people, the specific comma convention depicted here is only considered normal in the Anglo-Saxon world; conventions for writing large numbers in full vary considerably across cultures. For example, in countries where the comma is used as a {{w|decimal separator}} (including Europe outside the UK), one would write the number as 25.259.974.097.204 (or 25'259'974'097'204 in Switzerland, or 25 259 974 097 204 in Poland, France and Estonia). Under the {{w|Indian numbering system}}, this number would be written as 25,25,997,40,97,204.
|-
| 25 Trillion
| Normal Person
| This is the number, rounded to trillions in the normal fashion.
|-
| 25 Billion
| Old British Person
| In current English usage, across the Anglophonic world with some hold-outs, an n-illion means 10^(3n+3) as per the {{w|short scale}} system popularised by American influence in international trade, so a trillion means 10^12, as above. However, older British English use had an n-illion meaning 10^(6n) (i.e. the simpler calculation of ''million^n''), so a billion meant 10^12. The change stems from a 1974 commitment by Harold Wilson, the Prime Minister of the UK at the time, to change from the {{w|long scale}} (previously often described as the British system) to the short one for all official purposes.

Though not instantly widely adopted for common usage, the mid-'70s could therefore be considered the key turning point between when an older or younger British person learns (as the change filters through the system at various stages of education) what their "Billion"s and "Trillion"s are supposed to represent.

As well as 'traditionalist' British use, the long scale is widely used in the non-Anglophone world, in local language versions, though while the British system tended to infill n-and-a-half powers of the million with the term "thousand n-illion", the suffix "-illi''ard''", or equivalent, is often used for the thousands multiple directly atop the respective "-illion" point.
|-
|2.526x1013
|Scientist
|This number is formatted in {{w|scientific notation}}, using the exponent 1013.
|-
| 2.525997x1013
| Scientist trying to avoid rounding up
| Using as many decimal places as necessary until hitting a digit (0-4) that results in rounding down, even if it goes against the common scientific practice of reporting the correct amount of "significant figures". [[:File:large number formats.png|A previous version of the comic]] had a typo (the number was ''2.5997x1013''), but Randall updated the comic.
|-
| 2.526e13 or
2.526*10^13
| Software developer
| The first example is how the number would be expressed as a floating point number in scientific notation in [https://rosettacode.org/wiki/Literals/Floating_point every common programming language]. The second example is a technically correct way of expressing the same thing in some programming languages in which exponentiation is indicated by the ^ operator. However writing it that way instead of the first way would be considered quirky, as it is written as an instruction to the computer to calculate the product of a number with 10 raised to power 13, instead of just writing the number. A software developer might write it that way if they are a novice who is not familiar with the first notation. Or they could have an unusual personal preference that considers the second version easier to read. Perhaps the joke for the second version is that it is the standard scientific notation with the x for multiplication and superscript for raising to a power replaced with the notation used in many programming languages of * and ^, i.e., a software developer writing down a number in scientific notation, not necessarily while writing a program, would by habit write a * for multiplication and a ^ for exponentiation.
|-
| 25,259,973,541,888
| Software developer who forgot about floats
| The two most common computer {{w|Floating-point arithmetic|floating-point}} formats are the IEEE 754 {{w|Single-precision floating-point format|single-precision}} and {{w|Double-precision floating-point format|double-precision}} representations. These are ''binary'' floating-point formats, representing numbers as the quantity ''a'' × 2''e'', for some fractional number ''a'' and exponent ''e''. Both the values ''a'' and ''e'' have a fixed size in bits, and therefore a finite range. In single-precision, ''a'' and ''e'' have (effectively) 24 and 8 bits, respectively, while in double precision the effective sizes are 53 and 11 bits.

Fully representing the number 25,259,974,097,204 (in any format) requires at least 45 bits. Therefore this number cannot be represented exactly as a single-precision float. The closest possible representations are 0.717931628 × 245 and 0.717931688 × 245; these work out to 25,259,973,541,888 and 25,259,975,639,040, respectively. Of these, the one ending in 888 is considerably closer to the original, so is chosen due to {{w|rounding}}. (Naturally these numbers are represented internally in binary, not decimal; the actual representations, in hexadecimal, are <tt>0x0.b7ca5e</tt> × 2<tt></tt>0x2d and <tt>0x0.b7ca5f</tt> × 2<tt></tt>0x2d.)

In many programming languages, the keyword to request a single-precision floating-point variable is <tt>float</tt>, while the keyword to request double-precision is <tt>double</tt>. It is an easy mistake to make to forget about the limited precision available with type <tt>float</tt>, especially since its name sounds like what you want for "floating point". (Had the programmer remembered to use type <tt>double</tt>, the number 25,259,974,097,204 could have been represented exactly, as <tt>0x0.b7ca5e43c9a000</tt> × 2<tt></tt>0x2d.)
|-
| 1013
| Astronomer
| For extremely large distances, astronomers typically only care about orders of magnitude, e.g. whether a number is 1013, as opposed to 1012 or 1014. Randall often jokes about the lack of precision needed by astronomers, such as in [[2205: Types of Approximation]] where the astronomer-cosmologist is equally willing to make pi equal to one, or ten. The original number is rounded to the nearest power of ten.
|-
| {∅,{∅},{∅,{∅}},{∅,{∅},{...
| Set theorist
| In {{w|Zermelo–Fraenkel set theory}}, the natural numbers are defined recursively by letting 0 = ∅ (the {{w|empty set}}), and ''n'' + 1 = ''n'' ∪ {''n''}. So, every natural number ''n'' is the set of all natural numbers less than ''n'', and since 0 is defined as the empty set, all numbers are nested sets of empty sets. Note that writing out the full number in this fashion would take more than its square in number of characters; that is to say, if each character took up one square inch, this "number" would not fit on a square piece of paper whose edge reached to Jupiter.
|-
| 1,262,998,704,860 score and four
| Abraham Lincoln
| In the {{W|Gettysburg Address}}, Lincoln speaks the number "87" as "four score and seven" ("score" meaning "20"). Base-20 or {{w|vigesimal}} numeral systems are or have been used in pre-Columbian-American, African and many other cultures. In French it is used only for higher numbers (e.g. 92 = quatre-vingt-douze). In English it can appear in certain archaic and classic contexts, such as the King James translation of the Bible ("threescore years and ten" to be the life expectancy of a human according to Psalm 90:10). In these cases, a number is written in "score" (multiples of 20) plus a remainder. In this case 1,262,998,704,860 * 20 + 4 yields the exact number.
|-
| 10^13.4024 ''(title text)''
| A person who has come back to numbers after a journey deep into some random theoretical field
| In some fields of mathematics, especially those dealing with very {{w|large numbers}}, numbers are sometimes represented by raising ten (or some other convenient base) to an oddly precise power, to facilitate comparison of their magnitudes without filling up pages upon pages of digits. An example of this is {{w|Skewes's number}}, which is formally calculated to be ''e''''e''''e''79, but is more commonly approximated as 10101034. 13.4024 is a rounded version of the {{w|common logarithm}} of 25,259,974,097,204 (log10 25,259,974,097,204 = 13.4024329009); thus, this "format" is still mathematically correct, but uncommon. However, only by using many more digits will the result get close enough to be rounded to the original number 10^13,40243290087302 = 25,259,974,097,203.5, which would round up to the correct number. This number 10^13.4024 = 25,258,060,548,319.6 deviating almost 2 billion from the correct number
|}

==Transcript==
:[A panel only with text. At the top there is four lines of explanatory text. Below that are 2 columns with 5 rows of number formats. Each numerical format is in red, with black text explaining the format below it.]

:<big>What the way you write large numbers says about you</big>
:(Using the approximate current distance to Jupiter in inches as an example)

:25,259,974,097,204
:Normal person

:25 trillion
:Normal person

:25 billion
:Old British person

:2.526x1013
:Scientist

:2.525997x1013
:Scientist trying to avoid rounding up

:2.526e13 or 2.526*10^13
:Software developer

:25,259,973,541,888
:Software developer who forgot about floats

:1013
:Astronomer

:{∅,{∅},{∅,{∅}},{∅,{∅},{...
:Set theorist

:1,262,998,704,860 score and four
:Abraham Lincoln

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Programming]]
[[Category:Math]]
[[Category:Astronomy]]
[[Category:Science]]
[[Category:Comics featuring politicians]]

2319: Large Number Formats

2020-06-14T06:44:04Z

Ajlee2006: it's distance in inches not cm

{{comic
| number = 2319
| date = June 12, 2020
| title = Large Number Formats
| image = large number formats-2.png
| titletext = 10^13.4024: A person who has come back to numbers after a journey deep into some random theoretical field
}}

==Explanation==
{{incomplete|Created by ABRAHAM LINCOLN. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic shows what the way you write large numbers says about you. Different people use different methods to express large numbers. And this comic claims it can tell something about you based on the way you format large numbers. In this way the comic is similar in idea as [[977: Map Projections]], where it was your choice of map projections that could tell something about you.

See the [[#Table of types|table]] below for each of the 10 different ways to express large numbers, plus the 11th mentioned in the title text.

The number used as an example is the [https://www.wolframalpha.com/input/?i=Distance+to+Jupiter+in+inches approximate distance] from the planet {{w|Earth}} to the planet {{w|Jupiter}} as of the release day of the comic on June 12th 2020, in {{w|inch|inches}} (1 inch = 2.54 cm).

Two days after the release of the comic the following text could be found on [https://theskylive.com/jupiter-info Jupiter info] on [https://theskylive.com/ The Sky Live].
:The distance of Jupiter from Earth is currently 640,084,108 kilometers, equivalent to 4.278698 Astronomical Units. Light takes 35 minutes and 35.0908 seconds to travel from Jupiter and arrive to us.

64,008,410,800,000 cm / 2.54 inches/cm = 25,200,161,732,283 inches - much less than the number used in the comic. But Jupiter's distance to Earth changes quite fast, and was decreasing at the time of the comics release.

According to a graph of the distance as a function of time on The Sky Live, the distance on the release day was 643,1 million km. This will give 25,313 which the used number will round to. But still it is quite far from the one used.

The used number 25,259,974,097,204 is equivalent to 641,6 million km. On June 13th the distance is given as 641,7 million km in the graph on The Sky Live, very close to the number used. As this was the day after the release of this comic, it seems like [[Randall]] used a different distance than the exact one for the release day. Could also be that he used an average for June which would be 642 million km based on the average of the distance on June and July 1st.

==Table of types==
{| class="wikitable"
|-
! Number
! Type of person
! Notes
|-
| 25,259,974,097,204
| Normal Person
| This is the full number, 25259974097204, written out in the normal fashion, with commas to indicate powers of 1000. Although writing out the number in full is indeed a common action for normal people, the specific comma convention depicted here is only considered normal in the Anglo-Saxon world; conventions for writing large numbers in full vary considerably across cultures. For example, in countries where the comma is used as a {{w|decimal separator}} (including Europe outside the UK), one would write the number as 25.259.974.097.204 (or 25'259'974'097'204 in Switzerland, or 25 259 974 097 204 in Poland, France and Estonia). Under the {{w|Indian numbering system}}, this number would be written as 25,25,997,40,97,204.
|-
| 25 Trillion
| Normal Person
| This is the number, rounded to trillions in the normal fashion.
|-
| 25 Billion
| Old British Person
| In current English usage, across the Anglophonic world with some hold-outs, an n-illion means 10^(3n+3) as per the {{w|short scale}} system popularised by American influence in international trade, so a trillion means 10^12, as above. However, older British English use had an n-illion meaning 10^(6n) (i.e. the simpler calculation of ''million^n''), so a billion meant 10^12. The change stems from a 1974 commitment by Harold Wilson, the Prime Minister of the UK at the time, to change from the {{w|long scale}} (previously often described as the British system) to the short one for all official purposes.

Though not instantly widely adopted for common usage, the mid-'70s could therefore be considered the key turning point between when an older or younger British person learns (as the change filters through the system at various stages of education) what their "Billion"s and "Trillion"s are supposed to represent.

As well as 'traditionalist' British use, the long scale is widely used in the non-Anglophone world, in local language versions, though while the British system tended to infill n-and-a-half powers of the million with the term "thousand n-illion", the suffix "-illi''ard''", or equivalent, is often used for the thousands multiple directly atop the respective "-illion" point.
|-
|2.526x1013
|Scientist
|This number is formatted in {{w|scientific notation}}, using the exponent 1013.
|-
| 2.525997x1013
| Scientist trying to avoid rounding up
| Using as many decimal places as necessary until hitting a digit (0-4) that results in rounding down, even if it goes against the common scientific practice of reporting the correct amount of "significant figures". [[:File:large number formats.png|A previous version of the comic]] had a typo (the number was ''2.5997x1013''), but Randall updated the comic.
|-
| 2.526e13 or
2.526*10^13
| Software developer
| The first example is how the number would be expressed as a floating point number in scientific notation in [https://rosettacode.org/wiki/Literals/Floating_point every common programming language]. The second example is a technically correct way of expressing the same thing in some programming languages in which exponentiation is indicated by the ^ operator. However writing it that way instead of the first way would be considered quirky, as it is written as an instruction to the computer to calculate the product of a number with 10 raised to power 13, instead of just writing the number. A software developer might write it that way if they are a novice who is not familiar with the first notation. Or they could have an unusual personal preference that considers the second version easier to read. Perhaps the joke for the second version is that it is the standard scientific notation with the x for multiplication and superscript for raising to a power replaced with the notation used in many programming languages of * and ^, i.e., a software developer writing down a number in scientific notation, not necessarily while writing a program, would by habit write a * for multiplication and a ^ for exponentiation.
|-
| 25,259,973,541,888
| Software developer who forgot about floats
| The two most common computer {{w|Floating-point arithmetic|floating-point}} formats are the IEEE 754 {{w|Single-precision floating-point format|single-precision}} and {{w|Double-precision floating-point format|double-precision}} representations. These are ''binary'' floating-point formats, representing numbers as the quantity ''a'' × 2''e'', for some fractional number ''a'' and exponent ''e''. Both the values ''a'' and ''e'' have a fixed size in bits, and therefore a finite range. In single-precision, ''a'' and ''e'' have (effectively) 24 and 8 bits, respectively, while in double precision the effective sizes are 53 and 11 bits.

Fully representing the number 25,259,974,097,204 (in any format) requires at least 45 bits. Therefore this number cannot be represented exactly as a single-precision float. The closest possible representations are 0.717931628 × 245 and 0.717931688 × 245; these work out to 25,259,973,541,888 and 25,259,975,639,040, respectively. Of these, the one ending in 888 is considerably closer to the original, so is chosen due to {{w|rounding}}. (Naturally these numbers are represented internally in binary, not decimal; the actual representations, in hexadecimal, are <tt>0x0.b7ca5e</tt> × 2<tt></tt>0x2d and <tt>0x0.b7ca5f</tt> × 2<tt></tt>0x2d.)

In many programming languages, the keyword to request a single-precision floating-point variable is <tt>float</tt>, while the keyword to request double-precision is <tt>double</tt>. It is an easy mistake to make to forget about the limited precision available with type <tt>float</tt>, especially since its name sounds like what you want for "floating point". (Had the programmer remembered to use type <tt>double</tt>, the number 25,259,974,097,204 could have been represented exactly, as <tt>0x0.b7ca5e43c9a000</tt> × 2<tt></tt>0x2d.)
|-
| 1013
| Astronomer
| For extremely large distances, astronomers typically only care about orders of magnitude, e.g. whether a number is 1013, as opposed to 1012 or 1014. Randall often jokes about the lack of precision needed by astronomers, such as in [[2205: Types of Approximation]] where the astronomer-cosmologist is equally willing to make pi equal to one, or ten. The original number is rounded to the nearest power of ten.
|-
| {∅,{∅},{∅,{∅}},{∅,{∅},{...
| Set theorist
| In {{w|Zermelo–Fraenkel set theory}}, the natural numbers are defined recursively by letting 0 = ∅ (the {{w|empty set}}), and ''n'' + 1 = ''n'' ∪ {''n''}. So, every natural number ''n'' is the set of all natural numbers less than ''n'', and since 0 is defined as the empty set, all numbers are nested sets of empty sets. Note that writing out the full number in this fashion would take more than its square in number of characters; that is to say, if each character took up one square inch, this "number" would not fit on a square piece of paper whose edge reached to Jupiter.
|-
| 1,262,998,704,860 score and four
| Abraham Lincoln
| In the {{W|Gettysburg Address}}, Lincoln speaks the number "87" as "four score and seven" ("score" meaning "20"). Base-20 or {{w|vigesimal}} numeral systems are or have been used in pre-Columbian-American, African and many other cultures. In French it is used only for higher numbers (e.g. 92 = quatre-vingt-douze). In English it can appear in certain archaic and classic contexts, such as the King James translation of the Bible ("threescore years and ten" to be the life expectancy of a human according to Psalm 90:10). In these cases, a number is written in "score" (multiples of 20) plus a remainder. In this case 1,262,998,704,860 * 20 + 4 yields the exact number.
|-
| 10^13.4024 ''(title text)''
| A person who has come back to numbers after a journey deep into some random theoretical field
| In some fields of mathematics, especially those dealing with very {{w|large numbers}}, numbers are sometimes represented by raising ten (or some other convenient base) to an oddly precise power, to facilitate comparison of their magnitudes without filling up pages upon pages of digits. An example of this is {{w|Skewes's number}}, which is formally calculated to be ''e''''e''''e''79, but is more commonly approximated as 10101034. 13.4024 is a rounded version of the {{w|common logarithm}} of 25,259,974,097,204 (log10 25,259,974,097,204 = 13.4024329009); thus, this "format" is still mathematically correct, but uncommon. However, only by using many more digits will the result get close enough to be rounded to the original number 10^13,40243290087302 = 25,259,974,097,203.5, which would round up to the correct number. This number 10^13.4024 = 25,258,060,548,319.6 deviating almost 2 billion from the correct number
|}

==Transcript==
:[A panel only with text. At the top there is four lines of explanatory text. Below that are 2 columns with 5 rows of number formats. Each numerical format is in red, with black text explaining the format below it.]

:<big>What the way you write large numbers says about you</big>
:(Using the approximate current distance to Jupiter in inches as an example)

:25,259,974,097,204
:Normal person

:25 trillion
:Normal person

:25 billion
:Old British person

:2.526x1013
:Scientist

:2.525997x1013
:Scientist trying to avoid rounding up

:2.526e13 or 2.526*10^13
:Software developer

:25,259,973,541,888
:Software developer who forgot about floats

:1013
:Astronomer

:{∅,{∅},{∅,{∅}},{∅,{∅},{...
:Set theorist

:1,262,998,704,860 score and four
:Abraham Lincoln

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Programming]]
[[Category:Math]]
[[Category:Astronomy]]
[[Category:Science]]
[[Category:Comics featuring politicians]]

Thing Explainer

2020-03-31T09:20:51Z

Ajlee2006:

{{TOC}}
[[File:ThingExplainerBookCover.png|frame|right|General book cover]]

''Thing Explainer: Complicated Stuff in Simple Words'' is a book by [[Randall|Randall Munroe]] where things are explained in the style of [[Up Goer Five]] (which is also included in the book), using only {{w|blueprint}} like drawings and a vocabulary of the 1,000 (or ''ten hundred'') most common words in the English language. Randall found his own method to determine which words would go on his list, a list that is revealed in the book. (It can also be found [https://www.xkcd.com/simplewriter/words.js here].)

The book explores, among other things, computer buildings (datacenters), the flat rocks we live on (tectonic plates), the things you use to steer a plane (airliner cockpit controls), and the little bags of water you're made of (cells). See a summary below and also the [[#Things in this book by page|entire index from the book]] listing all the 45 different explanations.

''Thing Explainer'' is Randall's second published book, not including xkcd comic books, which he announced on May 13th, 2015 in [http://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ the blag] following the amazing success of his [[what if%3F#The book|what if? book]] based on the [[what if?]] blog.

The book is a collection of diagrams and line drawings similar in style to the Up Goer Five comic, which can also be purchased as a poster. It was [[#Release day|published]] by {{w|Houghton Mifflin Harcourt}} on November 24th and is available from among others {{w|Amazon.com|Amazon}} to which [http://amzn.to/1GCXMJ5 a link] has been posted on xkcd for a long time.

When the book was released Randall had ''Minute Physics'' do a "commercial" [https://youtu.be/2p_8gx-XHJo version of the Upgoer comic].

==Release day==
On the day of the book's release (even though it was a Tuesday) Randall also released the comic '''[[1608: Hoverboard]]''', which was a direct celebration of the book's release (it says so in the comic). But it was far from being a small or normal comic! It was the first "real" game comic released on xkcd (albeit not the first [[:Category:Interactive comics|interactive comic]]). In the style of [[1110: Click and Drag]] it was possible to move around in a very much larger picture than what was shown in the frame. But this is '''not done''' by clicking and dragging though, instead the user controls [[Cueball]] on a {{w|hoverboard}} (hence the title of the comic) by using the arrow keys, assuming that the user is on a desktop computer or a laptop. If he/she is on a mobile device such as a smartphone, [[Cueball]] is controlled by tilting the device.

There are many themes and references throughout the game, but the two main themes are {{w|Star Wars}} (the largest part to the right part) and {{w|The Lord of the Rings}} to the left. Several references goes back to the book from this comic. These are [[1608:_Hoverboard#Reference_to_Thing_Explainer|listed in the explanation]] for the hoverboard comic.

On the release day Randall also released a '''[http://www.xkcd.com/simplewriter/ simple writer]''' that would only accept the thousand words listed at the back of the book under ''The ten hundred words people use the most''. In this way others can try to create simple explanations themselves.

==Summary==
Have you ever tried to learn more about some incredible thing, only to be frustrated by incomprehensible jargon? Randall Munroe is here to help. In ''Thing Explainer'', he uses line drawings and only the thousand (or, rather, “ten hundred”) most common words to provide simple explanations for some of the most interesting stuff there is, including:

*food-heating radio boxes (microwaves)
*tall roads (bridges)
*computer buildings (datacenters)
*the shared space house (the International Space Station)
*the other worlds around the sun (the solar system)
*the big flat rocks we live on (tectonic plates)
*the pieces everything is made of (the periodic table)
*planes with turning wings (helicopters)
*boxes that make clothes smell better (washers and dryers)
*the bags of stuff inside you (cells)

How do these things work? Where do they come from? What would life be like without them? And what would happen if we opened them up, heated them up, cooled them down, pointed them in a different direction, or pressed this button? In ''Thing Explainer'', Munroe gives us the answers to these questions and so many more. Funny, interesting, and always understandable, this book is for anyone—age 5 to 105—who has ever wondered how things work, and why.

==Things in this book by page==
Below is the complete index of the book called ''Things in this book by page''. First is the simple title listed. Then follows the translation of this to normal language in brackets, with a wiki link to the most relevant page, based on the books material rather than the actual title. After "…" follows the page number for the start of that title as listed in the book:
*Pages before the books starts ({{w|Introduction (writing)|Introduction}}) … vii
*Shared space house ({{w|International Space Station}}) … 1
*Tiny bags of water you’re made of ({{w|Animal cell}}) … 2
*Heavy metal power building ({{w|Nuclear reactor}}) … 3
*Red world space car ({{w|Curiosity Rover}}) … 4
*Bag of stuff inside you ({{w|Human torso}}) … 6
*Boxes that make clothes smell better ({{w|Washing machine}} and {{w|Clothes dryer|dryer}}) … 7
*Earth’s surface ({{w|World map|Physical map of the Earth}}) … 8
*Under a car’s front cover ({{w|Car engine}}) … 11
*Sky boat with turning wings ({{w|Helicopter}}) … 13
*The US’s laws of the land ({{w|US Constitution}}) … 14
*The US<strike>’</strike>S ''Laws of the Land'' ({{w|USS Constitution}}) … 15
*Food-heating radio box ({{w|Microwave oven|Microwave}}) … 16
*Shape checker ({{w|Padlock}}) … 17
*Lifting room ({{w|Elevator}}) … 18
*Boat that goes under the sea ({{w|Submarine}}) … 19
*Box that cleans food holders ({{w|Dishwasher}}) … 20
*Big flat rocks we live on ({{w|Tectonic plates}}) … 21
*Cloud maps ({{w|Weather maps}}) … 22
*Tree ({{w|Tree}}) … 23
*Machine for burning cities ({{w|Thermonuclear weapon|Nuclear bomb}}) … 24
*Water room ({{w|Bathroom|Toilet and sink}}) … 25
*Computer building ({{w|Data center}}) … 26
*US Space Team's Up Goer Five ({{w|Saturn V rocket}}) … 28
*Sky boat pusher ({{w|Jet engine}}) … 30
*Stuff you touch to fly a sky boat ({{w|Cockpit}}) … 31
*Big tiny thing hitter ({{w|Large Hadron Collider}}) … 32
*Power boxes ({{w|Battery (electricity)|Batteries}}) … 33
*Hole-making city boat ({{w|Oil platform|Oil-rig}}) … 34
*Stuff in the Earth we can burn ({{w|Mining|Mines}}) … 35
*Tall roads ({{w|Bridges}}) … 36
*Bending computer ({{w|Laptop}}) … 37
*Worlds around the sun ({{w|Solar system}}) … 38
*Picture taker ({{w|Camera}}) … 40
*Writing sticks ({{w|Pen}} and {{w|pencil}}) … 41
*Hand computer ({{w|Smart phone}}) … 42
*Colors of light ({{w|Electromagnetic spectrum}}) … 43
*The sky at night ({{w|Night sky}}) … 44
*The pieces everything is made of ({{w|Periodic table}}) … 47
*Our star ({{w|Sun}}) … 49
*How to count things ({{w|International System of Units|Units and measurement}}) … 50
*Room for helping people ({{w|Hospital bed}}) … 51
*Playing fields ({{w|Pitch (sports field)|Athletic fields}}) … 52
*Earth’s past ({{w|Period (geology)|Geologic periods of Earth}}) … 53
*Tree of life ({{w|Tree of life (biology)|Life’s family tree}}) … 54
*The ten hundred words people use the most ({{w|Most common words in English|The ten hundred most common words}} in {{w|English language|our language}}) … 57
*Helpers ({{w|Acknowledgment (creative arts and sciences)|Acknowledgments}}) … 63
*Sky toucher ({{w|Skyscraper}}) … 65

There are 45 entries, but with the introduction, the list of used words and the acknowledgments taking up three, the total ends up at 48 explanations.

==The ten hundred words people use the most==
*Since ''thousand'' is not among the 1000 most common words in the English language, he has to write it as ''ten hundred''.
**Also common is also not a common word (ironically enough).
*It is possible to check if a word is allowed by using his [http://www.xkcd.com/simplewriter/ simple writer].
**The list of allowed words can be found [https://www.xkcd.com/simplewriter/words.js here].
*He does not use numbers like 1, 5 or 1000 in the book. He writes them out with words. So he could not have written ''1000 words...''
**Not even in the ''How to count things'' explanation.
**Interestingly enough neither ''zero'' or ''nine'' is in the list
***But the other numbers from one to ten can be used as well as twenty, thirty and hundred. No other numbers work.
***Zero is thus written ''none'' and nine like ''the one after eight''.
**In the simple writer you can write numbers without getting an error.
***But except in the index (called the ''[[#Things in this book by page|Things in this book by page]]'') and on the page just before this, with the publication details, numbers are only used for page numbers at the bottom of the page, which is also the only numbers referenced to in the index.
*The list has been made by Randall himself from extensive searches of the use of words in different types of sources.
**Especially fiction texts was used, but he also searched through the text messages he had received from people as another source.
**He writes directly: ''This is '''my''' list of the ten hundred words people use the most.''
*He only included one version of a word in the list. But all the different forms/endings of those words are allowed, but they are not written in the list and thus also not counted towards the 1000 allowed words.
**Thus many more different words than 1000 can be used, but only words with 1000 different meanings are used!
**He mentions as an example the word ''talk'', which is on the list, and thus also ''talking'' and ''talked'' would be allowed.
***He also allows words that do not exist if they sound funny enough like ''talker''.
***This is similar to ''goer'' like in [[1133: Up Goer Five]] or ''Sky '''toucher''''' from the last explanation in the book.
**Another example is the word ''be'' which is in the list.
***This then allows for instance ''Am'', ''are'' and ''is'' to be used.
***Those words are thus not in the list.
***See example [[#References to comics|below]] regarding words used in an xkcd comic featured in the book.
*Some common swear words have been left out even though they would be in most "real" list with the top 1000 common words
**For instance ''fuck'' would most likely have made the cut and maybe also ''shit'', and probably also some less harsh swear words.
**As he writes in the notes at the bottom of the last page with the list of words:
***''I didn't want to use those words anyway.''
*In the section '''Helpers''' he specifically notes that he wants to thank people, even though their names are not in the list.
**So he writes them out anyway!

==References to comics==
*These obvious references have already been mentioned above:
**[[1133: Up Goer Five]]. But apart from the entire comic being in the book there are other references to the comic:
***The tip of the Saturn V rocket can be seen at the top of ''Sky Toucher''
***The moon lander (and two astronauts) can been seen on the Moon in ''Worlds Around the Sun''.
***In the explanation for ''The pieces everything is made of'' hydrogen is similarly "named" by showing a picture of the burning Hindenburg and using the same quote as in the comic, "Oh, the humanity", which becomes "Oh the Humans!" in the book vs. "Oh, the [Humans]!" in the comic.
**[[1608: Hoverboard]]. (See this [[1608:_Hoverboard#Reference_to_Thing_Explainer|extensive list]] of connections).
*But there are also other comics that are directly or indirectly references in the book.
**[[1388: Subduction License]] is one of the most obvious examples is this comic which is directly featured in the book:
***It is included as part of the explanation of the ''Big flat rocks we live on.''
***But it is only the three last panels after the first panel which is displayed.
***The reason the first panel is not included is of course the words ''Subduction License'' which would not be allowed in the book.
***The normal words in the two middle panels are all found in the list at the back of the book. That is some form of the words are.
****Here is what is written in these panels and below this a "translation" to the version of these words that can be found on the list (see [[#The ten hundred words people use the most|above]] for an explanation on this):
****What are you doing? Stop it! Stop it!
****What '''be''' you '''do'''? Stop it! Stop it!
****All versions of these words would be allowed in the book. But the last word, ''Augh'' is of course not on the list, mainly because it is not a real word but just a sound word for an exclamation. But it is left in for the sake of the comic.
**[[526: Converting to Metric]].
***It is just a more funny version of ''How to count things'' where only the volume segment has been left out.
***The only item going again in both is the weight of a cat, although this is listed as 4 kg in the comic and 5 kg in the book...
**[[1314: Photos]].
***There is a small drawing that is just a different version of the idea behind the comic (see more explanation on the comics explanation).
**[[1110: Click and Drag]].
***A very direct reference is found in ''Stuff you touch to fly a sky boat'' where Cueball with his balloon can be seen floating just outside the cockpit.
***But there are other less indirect references like the radio controlled helicopter chase across several longer and longer bridges in ''Tall roads'' where [[Megan]] in the end catches it with a fishing rod. In Click and Drag [[Beret Guy]] is [http://imgs.xkcd.com/clickdrag/1n1e.png chasing an RC helicopter] with a butterfly net. And butterfly nets are also used in the book for catching other strange tings, see more below.
**[[1655: Doomsday Clock]] as well as [[1626: Judgment Day]].
***Both came out shortly after the book, both concerns the weapons of mass destruction humanity has created.
***This is referenced both directly in ''Machine for burning cities'' and are also mentioned in ''Boat that goes under the sea''.
**[[1619: Watson Medical Algorithm]].
***In the explanation ''Colors of light'' for the electromagnetic spectrum, [[Ponytail]] as a doctor looks at a full body x-ray of [[Cueball]] and exclaims that ''... It looks like your body is full of bones'' to which Cueball replies ''Oh no! Is there any cure?'' Well if he meets Watson he might have them all removed.
***That comic came out about a month after the book so it may be viewed as a kind of reference to the problem with too many bones.
**[[1135: Arachnoneurology]].
***In the comic spiders weave a shirt for [[Beret Guy]] and under one of the bridges in ''Tall roads'' there is a ship whose sail is a spider web. [[:Category:Spiders|Spiders]] are also shown in ''Tree of Life'' where they are called ''Biters with eight legs''.
**[[1376: Jump]].
***Has some similarities to what happens with Cueball in ''Playing fields'' when he jumps to score with his basketball, but then just keeps floating up along a straight line until twice the height of the hoop he yells ''Help!''
*There are also several items that are more generally just often used in xkcd comic, and thus not specially a reference to a given comic but rather to an entire category. Here is a list of some of the categories that are referenced in the book:
**There are two [[:Category:Butterfly net|Butterfly nets]].
***Both in relation to catching a {{w|Ball (association football)|soccer football}}, both in ''Playing fields'' and in ''Hole-making city boat''.
**There are several [[:Category:Space probes|Space probes]] including all the [[:Category:Mars rovers|Mars rovers]] (see much more detail on these two category links).
***In ''Red world space car'' the {{w|Curiosity Rover}} is explained in details. But the rower is also shown inside the skyscraper in ''Sky Tougher''.
***In ''The sky at night'' {{w|Voyager 1}} is shown.
***Both of these as well as several other probes including all other successful missions to Mars are listed in ''Worlds around the sun''.
**There are several references to [[:Category:Sport|Sport]], including all the main ones with their own category as well.
***Especially in ''Playing fields'' where all of these major sports are mentioned:
****[[:Category:American football|American football]] aka ''Foot Ball (My country)''.
****[[:Category:Baseball|Baseball]] aka ''Stick Ball''. This is also played inside the skyscraper in ''Sky toucher''.
****[[:Category:Basketball|Basketball]] aka ''Circle Ball''.
****[[:Category:Soccer|Soccer]] aka ''Foot Ball (Most other countries)''. This is also played on top of the Oil rig in ''Hole-making city boat''
***Other sports mentioned in that explanation are:
****{{w|Volleyball}} aka ''Hand and Arm Ball''
****{{w|Tennis}} aka ''Circle-Stick Ball''
****{{w|Ice Hockey}} aka ''Sliding around with sticks''
***Finally a few more sports is just depicted without names:
****{{w|Pole vaulting}}
****{{w|Karate}}
****{{w|Poohsticks}}, i.e. throwing sticks in the water from a bridge to see which comes first to the other side of the bridge...
***Other explanation with sport are
****''Hole-making city boat'' with both soccer, {{w|table tennis}} and {{w|Pool (cue sports)|pool}}
****{{w|Ten pin bowling}} is depicted three times with bowling alleys in the hull of the ship in ''The USS Laws of the Land'' and on the suspension of the longest bridge in ''Tall roads'' and a bowling alley is used for measuring length in ''How to count things.''
****''Heavy metal power building'' with two people {{w|fencing}}.
**[[:Category:Animals|Animals]] are a big part of several comics:
***''Tree of life'' is "simply" about all life, and here almost all animals used regularly in xkcd are mentioned.
***''Tree'' shows lots of the life that can live in or near a tree and thus also several animals.
***A {{w|pegasus}} like horse, but with helicopter wings instead of bird wings are shown in ''Sky boat with turning wings''.
***{{w|Octopuses}} are used in six explanations:
****''Shared space house'', ''The USS Laws of the Land'' (two), ''Big flat rocks we live on'', ''Picture taker'', ''Writing sticks'' and ''Tree of life''.
***[[:Category:Sharks|Sharks]] are used in six explanations:
****''Heavy metal power building'', ''The USS Laws of the Land'', ''Big tiny thing hitter'', ''Hole-making city boat'', ''Tree of life'' and ''Sky toucher'' (two).
****The shark's situation in ''Big tiny thing hitter'' reminds a little of the shark in [[585: Outreach]].
***[[:Category:Giraffes|Giraffes]] are used twice
****Four wight weight and length in ''How to count things'' and of course in the ''Tree of life''.
***[[:Category:Dinosaurs|Dinosaurs]] are not prominently featured but they are in two explanations:
****In ''Tree of life'' three types of dinosaurs are shown, including both [[:Category:Velociraptors|Velociraptors]] and [[:Category:Apatosaurus|Apatosaurus]].
****The latter type, Apatosaurus, has also managed to sneak into the ''Sky toucher'', even though it is ''not allowed''.
***[[:Category:Squirrels|Squirrels]] are used in four explanations.
****The most noticeable is in the explanation for ''Boxes that make clothes smell better'' where the drawing of the squirrel at the bottom right even have a notation. Above the squirrel there is an arrow pointing to it and this text:
::::"'''Wait'''
::::Why is this in your house?"
:::*The other squirrels are under the the pipe at the bottom of the explanation for ''Big tiny thing hitter'', in the top of the ''Tree'' and of course in the ''Tree of life''.
::*There are plenty of other animals including for instance {{w|Whales}} and {{w|ants}} who appear in several explanations

==Book Cover==
[[Cueball]] can be seen on the cover overlooking some of the labeled pictures. It was thus already early clear that the book would explore the themes labeled on the front cover which includes astronomy, constellations, and geology.

There are several funny "explanations" on the cover, like labels on arrows pointing to the title and to Randall's name explaining that this is:
*Big words that tell you what this book is
*My name

The back cover of the book was also available: 
[[File:ThingExplainerBookBackCover.png]]

==Preview pages==
*Part of the Curiosity entry (note that red was not used inside the book, only blue):
[[File:Space Car.jpeg]]

== Promotion at the xkcd home page ==
*Already on [http://web.archive.org/web/20150514053623/http://www.xkcd.com/ May 14th 2015] the first promotion of the book appeared at the top in the [[xkcd Header text]] of the xkcd home page. This was more than half a year before the release of the book.
**See the first entry described [[xkcd_Header_text#2015-05-14_-_New_book_Thing_Explainer|here]], and other changes will be mentioned above.
*While [[1611: Baking Soda and Vinegar]] was on the front page (2015-12-03), and until the comic [[1612: Colds]] came out, the top part of xkcd had been changed to [http://web.archive.org/web/20151203234149/http://xkcd.com/ promote the book], (see the image here below).
**The entire section was a link to [http://www.amazon.com/gp/product/0544668251/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0544668251&linkCode=as2&tag=thekcs-20&linkId=S4XRZJJKSMHOWEQU the book on amazon.com]
*Already later on the release day of Colds, (2015-12-04) it was moved to [http://web.archive.org/web/20151204190925/http://xkcd.com/ bottom section] of xkcd.
*But a [http://web.archive.org/web/20160401175527/https://www.xkcd.com/ commercial stayed at the top in the header] all the way until the problems with the [http://web.archive.org/web/20160401204749/https://xkcd.com/ April 1st comics release] in 2016, [[1663: Garden]].
**The commercial from above still stayed at the bottom below the comics even after April 1st 2016, until [http://web.archive.org/web/20160418061448/http://xkcd.com/ April 18th 2016].
**On [http://web.archive.org/web/20160418185337/http://xkcd.com/ April 19th 2016] the last reference to Thing Explainer disappeared from main page.
[[File:Thing Explainer promoted on xkcd.PNG]]

{{comic discussion}}

[[Category:Meta]]
[[Category:Simplified language]]

Thing Explainer

2020-03-31T09:19:34Z

Ajlee2006: added the list of words

{{TOC}}
[[File:ThingExplainerBookCover.png|frame|right|General book cover]]

''Thing Explainer: Complicated Stuff in Simple Words'' is a book by [[Randall|Randall Munroe]] where things are explained in the style of [[Up Goer Five]] (which is also included in the book), using only {{w|blueprint}} like drawings and a vocabulary of the 1,000 (or ''ten hundred'') most common words in the English language. Randall found his own method to determine which words would go on his list, a list that is revealed in the book.

The book explores, among other things, computer buildings (datacenters), the flat rocks we live on (tectonic plates), the things you use to steer a plane (airliner cockpit controls), and the little bags of water you're made of (cells). See a summary below and also the [[#Things in this book by page|entire index from the book]] listing all the 45 different explanations.

''Thing Explainer'' is Randall's second published book, not including xkcd comic books, which he announced on May 13th, 2015 in [http://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ the blag] following the amazing success of his [[what if%3F#The book|what if? book]] based on the [[what if?]] blog.

The book is a collection of diagrams and line drawings similar in style to the Up Goer Five comic, which can also be purchased as a poster. It was [[#Release day|published]] by {{w|Houghton Mifflin Harcourt}} on November 24th and is available from among others {{w|Amazon.com|Amazon}} to which [http://amzn.to/1GCXMJ5 a link] has been posted on xkcd for a long time.

When the book was released Randall had ''Minute Physics'' do a "commercial" [https://youtu.be/2p_8gx-XHJo version of the Upgoer comic].

==Release day==
On the day of the book's release (even though it was a Tuesday) Randall also released the comic '''[[1608: Hoverboard]]''', which was a direct celebration of the book's release (it says so in the comic). But it was far from being a small or normal comic! It was the first "real" game comic released on xkcd (albeit not the first [[:Category:Interactive comics|interactive comic]]). In the style of [[1110: Click and Drag]] it was possible to move around in a very much larger picture than what was shown in the frame. But this is '''not done''' by clicking and dragging though, instead the user controls [[Cueball]] on a {{w|hoverboard}} (hence the title of the comic) by using the arrow keys, assuming that the user is on a desktop computer or a laptop. If he/she is on a mobile device such as a smartphone, [[Cueball]] is controlled by tilting the device.

There are many themes and references throughout the game, but the two main themes are {{w|Star Wars}} (the largest part to the right part) and {{w|The Lord of the Rings}} to the left. Several references goes back to the book from this comic. These are [[1608:_Hoverboard#Reference_to_Thing_Explainer|listed in the explanation]] for the hoverboard comic.

On the release day Randall also released a '''[http://www.xkcd.com/simplewriter/ simple writer]''' that would only accept the thousand words listed at the back of the book under ''The ten hundred words people use the most''. In this way others can try to create simple explanations themselves.

==Summary==
Have you ever tried to learn more about some incredible thing, only to be frustrated by incomprehensible jargon? Randall Munroe is here to help. In ''Thing Explainer'', he uses line drawings and only the thousand (or, rather, “ten hundred”) most common words to provide simple explanations for some of the most interesting stuff there is, including:

*food-heating radio boxes (microwaves)
*tall roads (bridges)
*computer buildings (datacenters)
*the shared space house (the International Space Station)
*the other worlds around the sun (the solar system)
*the big flat rocks we live on (tectonic plates)
*the pieces everything is made of (the periodic table)
*planes with turning wings (helicopters)
*boxes that make clothes smell better (washers and dryers)
*the bags of stuff inside you (cells)

How do these things work? Where do they come from? What would life be like without them? And what would happen if we opened them up, heated them up, cooled them down, pointed them in a different direction, or pressed this button? In ''Thing Explainer'', Munroe gives us the answers to these questions and so many more. Funny, interesting, and always understandable, this book is for anyone—age 5 to 105—who has ever wondered how things work, and why.

==Things in this book by page==
Below is the complete index of the book called ''Things in this book by page''. First is the simple title listed. Then follows the translation of this to normal language in brackets, with a wiki link to the most relevant page, based on the books material rather than the actual title. After "…" follows the page number for the start of that title as listed in the book:
*Pages before the books starts ({{w|Introduction (writing)|Introduction}}) … vii
*Shared space house ({{w|International Space Station}}) … 1
*Tiny bags of water you’re made of ({{w|Animal cell}}) … 2
*Heavy metal power building ({{w|Nuclear reactor}}) … 3
*Red world space car ({{w|Curiosity Rover}}) … 4
*Bag of stuff inside you ({{w|Human torso}}) … 6
*Boxes that make clothes smell better ({{w|Washing machine}} and {{w|Clothes dryer|dryer}}) … 7
*Earth’s surface ({{w|World map|Physical map of the Earth}}) … 8
*Under a car’s front cover ({{w|Car engine}}) … 11
*Sky boat with turning wings ({{w|Helicopter}}) … 13
*The US’s laws of the land ({{w|US Constitution}}) … 14
*The US<strike>’</strike>S ''Laws of the Land'' ({{w|USS Constitution}}) … 15
*Food-heating radio box ({{w|Microwave oven|Microwave}}) … 16
*Shape checker ({{w|Padlock}}) … 17
*Lifting room ({{w|Elevator}}) … 18
*Boat that goes under the sea ({{w|Submarine}}) … 19
*Box that cleans food holders ({{w|Dishwasher}}) … 20
*Big flat rocks we live on ({{w|Tectonic plates}}) … 21
*Cloud maps ({{w|Weather maps}}) … 22
*Tree ({{w|Tree}}) … 23
*Machine for burning cities ({{w|Thermonuclear weapon|Nuclear bomb}}) … 24
*Water room ({{w|Bathroom|Toilet and sink}}) … 25
*Computer building ({{w|Data center}}) … 26
*US Space Team's Up Goer Five ({{w|Saturn V rocket}}) … 28
*Sky boat pusher ({{w|Jet engine}}) … 30
*Stuff you touch to fly a sky boat ({{w|Cockpit}}) … 31
*Big tiny thing hitter ({{w|Large Hadron Collider}}) … 32
*Power boxes ({{w|Battery (electricity)|Batteries}}) … 33
*Hole-making city boat ({{w|Oil platform|Oil-rig}}) … 34
*Stuff in the Earth we can burn ({{w|Mining|Mines}}) … 35
*Tall roads ({{w|Bridges}}) … 36
*Bending computer ({{w|Laptop}}) … 37
*Worlds around the sun ({{w|Solar system}}) … 38
*Picture taker ({{w|Camera}}) … 40
*Writing sticks ({{w|Pen}} and {{w|pencil}}) … 41
*Hand computer ({{w|Smart phone}}) … 42
*Colors of light ({{w|Electromagnetic spectrum}}) … 43
*The sky at night ({{w|Night sky}}) … 44
*The pieces everything is made of ({{w|Periodic table}}) … 47
*Our star ({{w|Sun}}) … 49
*How to count things ({{w|International System of Units|Units and measurement}}) … 50
*Room for helping people ({{w|Hospital bed}}) … 51
*Playing fields ({{w|Pitch (sports field)|Athletic fields}}) … 52
*Earth’s past ({{w|Period (geology)|Geologic periods of Earth}}) … 53
*Tree of life ({{w|Tree of life (biology)|Life’s family tree}}) … 54
*The ten hundred words people use the most ({{w|Most common words in English|The ten hundred most common words}} in {{w|English language|our language}}) … 57
*Helpers ({{w|Acknowledgment (creative arts and sciences)|Acknowledgments}}) … 63
*Sky toucher ({{w|Skyscraper}}) … 65

There are 45 entries, but with the introduction, the list of used words and the acknowledgments taking up three, the total ends up at 48 explanations.

==The ten hundred words people use the most==
*Since ''thousand'' is not among the 1000 most common words in the English language, he has to write it as ''ten hundred''.
**Also common is also not a common word (ironically enough).
*It is possible to check if a word is allowed by using his [http://www.xkcd.com/simplewriter/ simple writer].
**The list of allowed words can be found [https://www.xkcd.com/simplewriter/words.js here].
*He does not use numbers like 1, 5 or 1000 in the book. He writes them out with words. So he could not have written ''1000 words...''
**Not even in the ''How to count things'' explanation.
**Interestingly enough neither ''zero'' or ''nine'' is in the list
***But the other numbers from one to ten can be used as well as twenty, thirty and hundred. No other numbers work.
***Zero is thus written ''none'' and nine like ''the one after eight''.
**In the simple writer you can write numbers without getting an error.
***But except in the index (called the ''[[#Things in this book by page|Things in this book by page]]'') and on the page just before this, with the publication details, numbers are only used for page numbers at the bottom of the page, which is also the only numbers referenced to in the index.
*The list has been made by Randall himself from extensive searches of the use of words in different types of sources.
**Especially fiction texts was used, but he also searched through the text messages he had received from people as another source.
**He writes directly: ''This is '''my''' list of the ten hundred words people use the most.''
*He only included one version of a word in the list. But all the different forms/endings of those words are allowed, but they are not written in the list and thus also not counted towards the 1000 allowed words.
**Thus many more different words than 1000 can be used, but only words with 1000 different meanings are used!
**He mentions as an example the word ''talk'', which is on the list, and thus also ''talking'' and ''talked'' would be allowed.
***He also allows words that do not exist if they sound funny enough like ''talker''.
***This is similar to ''goer'' like in [[1133: Up Goer Five]] or ''Sky '''toucher''''' from the last explanation in the book.
**Another example is the word ''be'' which is in the list.
***This then allows for instance ''Am'', ''are'' and ''is'' to be used.
***Those words are thus not in the list.
***See example [[#References to comics|below]] regarding words used in an xkcd comic featured in the book.
*Some common swear words have been left out even though they would be in most "real" list with the top 1000 common words
**For instance ''fuck'' would most likely have made the cut and maybe also ''shit'', and probably also some less harsh swear words.
**As he writes in the notes at the bottom of the last page with the list of words:
***''I didn't want to use those words anyway.''
*In the section '''Helpers''' he specifically notes that he wants to thank people, even though their names are not in the list.
**So he writes them out anyway!

==References to comics==
*These obvious references have already been mentioned above:
**[[1133: Up Goer Five]]. But apart from the entire comic being in the book there are other references to the comic:
***The tip of the Saturn V rocket can be seen at the top of ''Sky Toucher''
***The moon lander (and two astronauts) can been seen on the Moon in ''Worlds Around the Sun''.
***In the explanation for ''The pieces everything is made of'' hydrogen is similarly "named" by showing a picture of the burning Hindenburg and using the same quote as in the comic, "Oh, the humanity", which becomes "Oh the Humans!" in the book vs. "Oh, the [Humans]!" in the comic.
**[[1608: Hoverboard]]. (See this [[1608:_Hoverboard#Reference_to_Thing_Explainer|extensive list]] of connections).
*But there are also other comics that are directly or indirectly references in the book.
**[[1388: Subduction License]] is one of the most obvious examples is this comic which is directly featured in the book:
***It is included as part of the explanation of the ''Big flat rocks we live on.''
***But it is only the three last panels after the first panel which is displayed.
***The reason the first panel is not included is of course the words ''Subduction License'' which would not be allowed in the book.
***The normal words in the two middle panels are all found in the list at the back of the book. That is some form of the words are.
****Here is what is written in these panels and below this a "translation" to the version of these words that can be found on the list (see [[#The ten hundred words people use the most|above]] for an explanation on this):
****What are you doing? Stop it! Stop it!
****What '''be''' you '''do'''? Stop it! Stop it!
****All versions of these words would be allowed in the book. But the last word, ''Augh'' is of course not on the list, mainly because it is not a real word but just a sound word for an exclamation. But it is left in for the sake of the comic.
**[[526: Converting to Metric]].
***It is just a more funny version of ''How to count things'' where only the volume segment has been left out.
***The only item going again in both is the weight of a cat, although this is listed as 4 kg in the comic and 5 kg in the book...
**[[1314: Photos]].
***There is a small drawing that is just a different version of the idea behind the comic (see more explanation on the comics explanation).
**[[1110: Click and Drag]].
***A very direct reference is found in ''Stuff you touch to fly a sky boat'' where Cueball with his balloon can be seen floating just outside the cockpit.
***But there are other less indirect references like the radio controlled helicopter chase across several longer and longer bridges in ''Tall roads'' where [[Megan]] in the end catches it with a fishing rod. In Click and Drag [[Beret Guy]] is [http://imgs.xkcd.com/clickdrag/1n1e.png chasing an RC helicopter] with a butterfly net. And butterfly nets are also used in the book for catching other strange tings, see more below.
**[[1655: Doomsday Clock]] as well as [[1626: Judgment Day]].
***Both came out shortly after the book, both concerns the weapons of mass destruction humanity has created.
***This is referenced both directly in ''Machine for burning cities'' and are also mentioned in ''Boat that goes under the sea''.
**[[1619: Watson Medical Algorithm]].
***In the explanation ''Colors of light'' for the electromagnetic spectrum, [[Ponytail]] as a doctor looks at a full body x-ray of [[Cueball]] and exclaims that ''... It looks like your body is full of bones'' to which Cueball replies ''Oh no! Is there any cure?'' Well if he meets Watson he might have them all removed.
***That comic came out about a month after the book so it may be viewed as a kind of reference to the problem with too many bones.
**[[1135: Arachnoneurology]].
***In the comic spiders weave a shirt for [[Beret Guy]] and under one of the bridges in ''Tall roads'' there is a ship whose sail is a spider web. [[:Category:Spiders|Spiders]] are also shown in ''Tree of Life'' where they are called ''Biters with eight legs''.
**[[1376: Jump]].
***Has some similarities to what happens with Cueball in ''Playing fields'' when he jumps to score with his basketball, but then just keeps floating up along a straight line until twice the height of the hoop he yells ''Help!''
*There are also several items that are more generally just often used in xkcd comic, and thus not specially a reference to a given comic but rather to an entire category. Here is a list of some of the categories that are referenced in the book:
**There are two [[:Category:Butterfly net|Butterfly nets]].
***Both in relation to catching a {{w|Ball (association football)|soccer football}}, both in ''Playing fields'' and in ''Hole-making city boat''.
**There are several [[:Category:Space probes|Space probes]] including all the [[:Category:Mars rovers|Mars rovers]] (see much more detail on these two category links).
***In ''Red world space car'' the {{w|Curiosity Rover}} is explained in details. But the rower is also shown inside the skyscraper in ''Sky Tougher''.
***In ''The sky at night'' {{w|Voyager 1}} is shown.
***Both of these as well as several other probes including all other successful missions to Mars are listed in ''Worlds around the sun''.
**There are several references to [[:Category:Sport|Sport]], including all the main ones with their own category as well.
***Especially in ''Playing fields'' where all of these major sports are mentioned:
****[[:Category:American football|American football]] aka ''Foot Ball (My country)''.
****[[:Category:Baseball|Baseball]] aka ''Stick Ball''. This is also played inside the skyscraper in ''Sky toucher''.
****[[:Category:Basketball|Basketball]] aka ''Circle Ball''.
****[[:Category:Soccer|Soccer]] aka ''Foot Ball (Most other countries)''. This is also played on top of the Oil rig in ''Hole-making city boat''
***Other sports mentioned in that explanation are:
****{{w|Volleyball}} aka ''Hand and Arm Ball''
****{{w|Tennis}} aka ''Circle-Stick Ball''
****{{w|Ice Hockey}} aka ''Sliding around with sticks''
***Finally a few more sports is just depicted without names:
****{{w|Pole vaulting}}
****{{w|Karate}}
****{{w|Poohsticks}}, i.e. throwing sticks in the water from a bridge to see which comes first to the other side of the bridge...
***Other explanation with sport are
****''Hole-making city boat'' with both soccer, {{w|table tennis}} and {{w|Pool (cue sports)|pool}}
****{{w|Ten pin bowling}} is depicted three times with bowling alleys in the hull of the ship in ''The USS Laws of the Land'' and on the suspension of the longest bridge in ''Tall roads'' and a bowling alley is used for measuring length in ''How to count things.''
****''Heavy metal power building'' with two people {{w|fencing}}.
**[[:Category:Animals|Animals]] are a big part of several comics:
***''Tree of life'' is "simply" about all life, and here almost all animals used regularly in xkcd are mentioned.
***''Tree'' shows lots of the life that can live in or near a tree and thus also several animals.
***A {{w|pegasus}} like horse, but with helicopter wings instead of bird wings are shown in ''Sky boat with turning wings''.
***{{w|Octopuses}} are used in six explanations:
****''Shared space house'', ''The USS Laws of the Land'' (two), ''Big flat rocks we live on'', ''Picture taker'', ''Writing sticks'' and ''Tree of life''.
***[[:Category:Sharks|Sharks]] are used in six explanations:
****''Heavy metal power building'', ''The USS Laws of the Land'', ''Big tiny thing hitter'', ''Hole-making city boat'', ''Tree of life'' and ''Sky toucher'' (two).
****The shark's situation in ''Big tiny thing hitter'' reminds a little of the shark in [[585: Outreach]].
***[[:Category:Giraffes|Giraffes]] are used twice
****Four wight weight and length in ''How to count things'' and of course in the ''Tree of life''.
***[[:Category:Dinosaurs|Dinosaurs]] are not prominently featured but they are in two explanations:
****In ''Tree of life'' three types of dinosaurs are shown, including both [[:Category:Velociraptors|Velociraptors]] and [[:Category:Apatosaurus|Apatosaurus]].
****The latter type, Apatosaurus, has also managed to sneak into the ''Sky toucher'', even though it is ''not allowed''.
***[[:Category:Squirrels|Squirrels]] are used in four explanations.
****The most noticeable is in the explanation for ''Boxes that make clothes smell better'' where the drawing of the squirrel at the bottom right even have a notation. Above the squirrel there is an arrow pointing to it and this text:
::::"'''Wait'''
::::Why is this in your house?"
:::*The other squirrels are under the the pipe at the bottom of the explanation for ''Big tiny thing hitter'', in the top of the ''Tree'' and of course in the ''Tree of life''.
::*There are plenty of other animals including for instance {{w|Whales}} and {{w|ants}} who appear in several explanations

==Book Cover==
[[Cueball]] can be seen on the cover overlooking some of the labeled pictures. It was thus already early clear that the book would explore the themes labeled on the front cover which includes astronomy, constellations, and geology.

There are several funny "explanations" on the cover, like labels on arrows pointing to the title and to Randall's name explaining that this is:
*Big words that tell you what this book is
*My name

The back cover of the book was also available: 
[[File:ThingExplainerBookBackCover.png]]

==Preview pages==
*Part of the Curiosity entry (note that red was not used inside the book, only blue):
[[File:Space Car.jpeg]]

== Promotion at the xkcd home page ==
*Already on [http://web.archive.org/web/20150514053623/http://www.xkcd.com/ May 14th 2015] the first promotion of the book appeared at the top in the [[xkcd Header text]] of the xkcd home page. This was more than half a year before the release of the book.
**See the first entry described [[xkcd_Header_text#2015-05-14_-_New_book_Thing_Explainer|here]], and other changes will be mentioned above.
*While [[1611: Baking Soda and Vinegar]] was on the front page (2015-12-03), and until the comic [[1612: Colds]] came out, the top part of xkcd had been changed to [http://web.archive.org/web/20151203234149/http://xkcd.com/ promote the book], (see the image here below).
**The entire section was a link to [http://www.amazon.com/gp/product/0544668251/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0544668251&linkCode=as2&tag=thekcs-20&linkId=S4XRZJJKSMHOWEQU the book on amazon.com]
*Already later on the release day of Colds, (2015-12-04) it was moved to [http://web.archive.org/web/20151204190925/http://xkcd.com/ bottom section] of xkcd.
*But a [http://web.archive.org/web/20160401175527/https://www.xkcd.com/ commercial stayed at the top in the header] all the way until the problems with the [http://web.archive.org/web/20160401204749/https://xkcd.com/ April 1st comics release] in 2016, [[1663: Garden]].
**The commercial from above still stayed at the bottom below the comics even after April 1st 2016, until [http://web.archive.org/web/20160418061448/http://xkcd.com/ April 18th 2016].
**On [http://web.archive.org/web/20160418185337/http://xkcd.com/ April 19th 2016] the last reference to Thing Explainer disappeared from main page.
[[File:Thing Explainer promoted on xkcd.PNG]]

{{comic discussion}}

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